Consider the case of a controversial cartoon. Not the notorious Danish cartoons, but a cartoon published in the New York Post last month. A response to revelations that emerged in February about the NYPD's large-scale spying on American Muslim students after 9/11, it portrayed three hook-nosed, turbaned terrorists complaining that the police were spying on them. In doing so, it insinuated a link between the terrorists the NYPD is meant to monitor and the innocent American citizens whose civil liberties were deliberately breached.

I was reminded of this cartoon during Irshad Manji's recent talk at a Free Speech Debate event at Oxford University. Manji opposes all legal prohibitions on free speech, even to the point of permitting the publication of death threats against herself. While certainly idiosyncratic, this position is internally consistent, avoiding the hypocrisy that habitually bedevils attempts to ban certain types of free speech on the grounds of offence but not others. However, once we accept that the state should not play the role of censor, an absolutist defence of free speech as "life itself", as Salman Rushdie once put it, cannot tell us how to judge between individual instances of its exercise.

Looking at a cartoon that portrays American Muslims as terrorists-to-be from the perspective of free speech versus censorship alone absolves us from asking what the intention behind it is, or what context it appears in. The context in this case is one of increasing Islamophobia in Europe and North America, from the furore caused by proposals for a mosque in Manhattan to the fact that provision of halal meat has become a defining issue in the French presidential campaign.

The depiction of Muslims in the New York Post as hook-nosed Semites is no coincidence, sharing much in common with the anti-Jewish stereotypes widely prevalent not so long ago, when attacks on Jews as people masqueraded as critiques of their religious practices. This makes it difficult to uphold a classical liberal distinction between criticising "beliefs" and criticising "people", for the two are conflated in the racialised manner in which Muslims are often discussed.

Nor is this a simple matter of isolating the far right, for anti-Muslim animus can unite liberals and conservatives, as demonstrated by the Danish cartoon controversy. For the right, Muslims are to be excluded for not fitting into a Christian conception of the west; for sections of the left, because Islam is regarded as alien to a secular Enlightenment defined as European in origin.

While they differ over the character of their preferred "reformist Islam", both Manji and the Islamists she castigates are on shared ground in assuming that the trouble lies in one interpretation of Islam and that the solution lies in another. But in fact the problem lies in framing this as a discussion about Islam as a religion to begin with, as happens in the never-ending debates about the compatibility of Islam with liberalism, democracy, or free speech. Such a framing puts the burden on a minority to prove its compatibility with the prejudices of a majority. This perpetuates the tendency, among both Muslims and non-Muslims, to think of Muslims as Muslims first and alone, rather than treating their concerns as those of any other citizen, for whom religion is one marker among many, including class and ethnicity.

"Moderate Muslims," Manji writes in Allah, Liberty and Love, "are so consumed with western colonialism that they've diverted themselves from dealing with the imperialists inside Islam." Yet the existence of Muslims who use accusations of Islamophobia as a political ploy to shut down dissent within Muslim communities does not make the reality of Islamophobia irrelevant. After all, antisemitism is no less real just because it has been exploited as a smear with which to silence critics of Israel. Muslims and non-Muslims alike have always engaged critically and creatively with the Islamic tradition, both reverently and irreverently.

Their right to do so must be beyond question. However, criticism of religion does not exist in a vacuum of ideas, abstracted from any wider political context. In this vein, it is worth asking what function the disproportionate fixation with diagnosing Islam's ills fulfils in much of Europe and North America today. Could this too be a political ploy, to disguise and displace deeper anxieties about the direction our societies are taking at a time of immense political and economic upheaval?